Cell lines and monoclonal antibodies (Mab) are indispensable tools for experimental investigations. This group has generated one of the largest cell banks of cultured melanocytes from normal skin, nevi, and primary and metastatic melanomas. The cell bank is continuously expanding due to the needs of all investigators of this program project. The objectives are to culture cells, characterize their phenotypes, freeze stocks and quality- control all cells regarding mycoplasma infections. Cultures are then distributed to all investigators within the program project and to other interested scientists. MAb are being produced for research projects using in vivo subtraction protocols to achieve a higher percentage of specific antibodies. Immunoglobulin production is tested before tissue culture supernatants of hybridomas producing anti-melanoma MAb are distributed to investigators within and outside the program project. MAb are purified from tissue culture supernatants and ascitic fluids of hybridoma-bearing mice. Overall, this Core will continue to provide efficient and high quality service to the participating laboratories.